Novel Approach for Deriving a State-Dependent Soil Constitutive Model Using Stress Probing Analysis

Nonlinearity, irreversibility, and state-dependency are prominent features of the mechanical behavior of soil. To develop a constitutive model for soil with a rigorous basis, a thorough understanding of its incremental stress-strain response is indispensable. In this study, a numerical stress probing technique, employing the discrete element method (DEM), is utilized to investigate the strain response of soil subjected to stress increments along different directions. The influence of density and stress state on the incremental behavior is systematically analyzed. A novel method is proposed to derive several essential components of the constitutive model from the response envelopes, including the yield surface, plastic flow direction, hardening rule, and plastic modulus. A state-dependent constitutive model is then formulated within the critical state framework, and its predictive capability is demonstrated by simulating soil behavior in both discrete element tests and laboratory tests under varying loading conditions.